The present invention generally relates to connectors, and more particularly to a connector comprising a plug which is detachably coupled to a socket.
An apparatus such as a computer is coupled to another apparatus via a cable. Recently, an optical fiber cable is used to couple two apparatuses. An optical plug having a ferrule is provided on a tip end of the conventional optical fiber cable, and this optical plug is inserted into and coupled to a socket provided on the apparatus. When the optical plug is coupled to the socket, tip ends of optical fibers of the optical fiber cable each confront a corresponding light emitting or light receiving element provided in the socket, and the two apparatuses are coupled optically by the optical fiber cable. However, at an optical coupling part where the tip end of each optical fiber and the corresponding light emitting or receiving element confront each other, both the tip end of the optical fiber and the corresponding light emitting or light receiving element must be positioned with a high accuracy. For this reason, it is undesirable for this optical coupling part to be movable, and it is desirable for the optical coupling part to be fixed.
Accordingly, an optical fiber cable has been devised in which the light emitting elements and/or light receiving elements and electronic circuits coupled thereto are provided within the optical plug so that the optical coupling part becomes fixed. In this csse, the optical coupling part becomes fixed although the optical fiber cable is used, and the coupling between the optical plug and the socket becomes an electrical coupling. In other words, contact pins of the optical plug make contact with corresponding contact members of the socket.
As one example of the conventional plug, there is a plug comprising a plurality of contact pins including a contact pin for grounding, and a metal shielding pipe surrounding the contact pins. A socket which is inserted with the plug comprises a grounding contact member for making contact with the contact member for grounding, a plurality of contact members for making contact with the corresponding contact pins other than the contact pin for grounding, and a grounding terminal member for making contact with the shielding pipe. The contact members and the grounding terminal member of the socket are soldered to corresponding wiring patterns on a printed circuit of an apparatus and are fixed on the printed circuit. The grounding contact member and the grounding terminal member are independent members and are soldered to a grounding pattern independently. For this reason, the number of grounding members is large, and there is a problem in that the operation of mounting the grounding members on the socket is troublesome to carry out.
In addition, the contact pins of the conventional plug are arranged so that tip ends thereof lie on the same plane, and the contact members of the conventional socket are similarly arranged so that ends thereof lie on the same plane. Hence, when the plug is inserted into the socket, there is a problem in that the contact pins for signal transmission and reception may make contact with the corresponding contact members before the contact pin for grounding and the contact pins for supplying power make contact with the corresponding contact members depending on the manner in which the plug is inserted into the socket. When the contact pins for signal transmission and reception make contact with the corresponding contact members before the contact pin for grounding and the contact pins for supplying power make contact with the corresponding contact members, signals may not be transmitted normally immediately after the plug is inserted into the socket, and a part of the circuit in the plug and/or the apparatus such as a CMOS type integrated circuit may become damaged.
On the other hand, the plug comprises a generally cylindrical holding member for holding the contact pins, and the holding member is provided within the shielding pipe. However, since the shielding pipe and the holding member are connected together by an adhesive, there is a problem in that the operation of connecting the shielding pipe and the holding member is troublesome to carry out.
Furthermore, in the conventional plug and socket, there is no special means for positioning the plug along a peripheral direction thereof when the plug is inserted into the socket. For this reasin, when inserting the plug into the socket, it is necessary for the operator to position the plug along the peripheral direction thereof and to visually confirm that the contact pins of the plug will make contact with the corresponding contact members of the socket. Thus, there is a problem in that the operation of inserting the plug into the socket is troublesome to carry out.
Moreover, a conventional connector comprising the plug and the socket is provided with no means for informing the operator that the operation of coupling the plug to the socket has been completed. For this reason, the operation of coupling the plug to the socket is carried out by inserting the plug into the socket to a position where the plug can no longer be inserted. However, even when the plug is inserted into the socket up to the position where the plug can no longer be inserted, it is uncertain whether or not the plug has actually been coupled to the socket.
On the other hand, in the case of the optical plug provided on the tip end of the optical fiber cable, the light emitting element is embeddedly provided within a molded synthetic resin support. Hence, only the light emitted from a front of the light emitting element is used as an optical signal by being supplied to the corresponding optical fiber, and there is a problem in that the light emitted from sides of the light emitting element is not effectively used for the signal transmission.